EXPERTS, HOW SUMMONED INTO COURT.
They Must Obey the Summons and Appear and be Sworn. In General they need Not Give their Opinions unless Duly Compensated.—An expert witness is brought into court like an ordinary witness by the usual process of the court. This process is, under the American system, an ordinary subpœna, and, being process of the court, whether or not he has been paid or promised compensation for giving his opinion he must obey the process to the extent at least of appearing in court when called, to be sworn. Interesting questions have been raised as to his obedience to the subpœna to the extent of testifying when he has not been compensated. It has been argued, and the argument is sustained by the decisions of courts of high authority in some States, that his knowledge and skill, acquired by study and by experience, is his property, of which he cannot be deprived without just compensation, under his constitutional rights guaranteed to him by the organic law of this country. On the other hand, in some other States it has been held that he is so far a necessary part of the judicial system that he may be called upon to give the results of his experience, knowledge, and skill forming his opinion, without payment other than the ordinary compensation to witnesses. It is believed, however, that the better opinion is the former; that he does not stand on the same footing as an ordinary witness, whose province it is to testify solely to matters of observation of fact, but that he stands in the position of one who has something to give; something to impart in the way of knowledge or experience, which is his property as much as any other thing movable or immovable of which he is possessed.
A somewhat different question has arisen in the case of a witness who, like a family physician or attending physician, has learned facts and has been paid for his attendance, or who exacts payment for his attendance, as a physician from his patient, and this question is; when such a professional man has been called upon to testify to the information he thus attained, whether he can be asked for, and required to give, opinions based on those facts? Necessarily, having learned the facts by observation, such as the appearance, symptoms, and actions of the patient, he is, when testifying as to these matters, nothing more or less than an ordinary witness, because he is testifying to matters of observation. As to these matters public policy requires, except so far as it has been modified, or rather extended, by our statutes which forbid testimony as to privileged communications, that he must testify, the same as any other witness. But suppose that, having so testified to the facts, he is asked to give his opinion; for example, in an insanity case, whether the symptoms that he found in his patient led him to the belief as a professional man of experience and skill that his patient was sane or insane. The question is, Can he be compelled to give that opinion, if he chooses to decline to give it without the promise or assurance of further compensation than the mere per diem fee and mileage of an ordinary witness? The best authority is to the effect that he must so testify, the reasoning of the court being that his opinion is only a part of what he derived from his original relation of physician to his patient. Wright v. The People, 112 Ill., 540; same case, 33 Alb. L. J., 79.
Same Rule in Civil and Criminal Cases.—The rule is the same whether the professional man is called to testify as an expert in civil or criminal cases. In either one he is not obliged to give an opinion as such, independent of a personal knowledge of the facts in the case, without being paid or assured reasonable compensation therefor. His proper course of conduct is, when he has obeyed the subpœna and is in the presence of the court and has been sworn, and the questions put by counsel disclose that the object of his examination is to elicit from him an opinion, to state to the court that he has not been paid any other compensation than that of an ordinary witness, and that he respectfully declines to give an opinion in the case as an expert, without compensation proportionate to the value of his opinion.[182]
Whether Witness Competent a Question for Court in Limine.—After the expert is placed upon the stand, as we have seen, the counsel upon the side of the case by which he is summoned interrogates him as to his capacity, the purpose of the interrogation being that his answers shall qualify him and show him to be an expert. Whether or not he is an expert so as to permit the giving of his opinion as part of the case to go to the jury, is for the court to decide in limine, that is, at the threshold, and as a matter of discretion, and the exercise of that discretion, if fair and reasonable, will not be disturbed upon appeal by the higher court. It is permissible, but also discretionary, after the counsel calls the witness and has apparently qualified him, for the counsel upon the other side to cross-examine the witness as to his qualifications before he is examined in chief, with a view of determining whether or not there are limitations upon those qualifications which should prevent the court from permitting him to testify as an expert. The general rule is as stated by Greenleaf in his work on Evidence, Sec. 440, that it is not necessary that the medical expert should have actually practised his profession. Nor is it essential that the witness should belong to any particular school of medicine. The law does not undertake to pass upon conflicting theories of medical practice, in determining the question of the qualification of a medical expert. It is proper, however, for counsel to inquire as to what school of medicine the witness is an adherent, because of its importance in weighing the value of his testimony after it has been given.
Persons Not Duly Licensed Sometimes Held Not Competent.—It has also been a mooted question in those States where it is necessary, in order to enable a person to practise physic or surgery, that he should be licensed, whether a person practising without a license, however extensive his reading and practice, would be considered qualified as an expert witness in a court of justice. This point, so far as diligent examination discloses, has not been determined in any reported case, although it has been suggested at nisi prius and has been, in one instance within the knowledge of the writer, decided that he is not to be considered an expert in matters involving medical knowledge and skill. The reasoning of the court was that the policy of the State is to prohibit persons not possessing the qualifications required to obtain a license, from acting in any capacity as professors and practitioners of medicine or surgery. If the witness is a member of the profession, legally qualified as such, it has been held that he is sufficiently qualified as an expert if he shows that he possesses the average ability of members of his profession. Hall v. Costello, 48 N. H., 176; Tellis v. Kidd, 12 Ala., 648; Wharton on Evidence, Sec. 446; Rogers on Expert Testimony, Secs. 17 and 18; Slocovich v. Orient Mutual Ins. Co., 108 N. Y., 56.
As to the question whether it is necessary that the witness should actually have practised his profession, see the last-cited text-writer, Secs. 43 and 44, who seems to have entertained views opposite to those stated by Professor Greenleaf.
Wharton on Evidence, Sec. 439, states the rule as follows: “He must have special, practical acquaintance with the immediate line of inquiry more than a mere vague, superficial knowledge. But he need not be acquainted with the differentia of the specific specialty under consideration.... A general knowledge of the department to which the specialty belongs would seem to be sufficient.”
Interested Persons may still Testify as Experts.—Since the law forbidding interested persons from being witnesses has been changed, it has been suggested that an interested person although otherwise qualified might not be a competent witness to give an opinion as an expert. But the established doctrine is that he may give such an opinion; the weight of it, however, would be for the jury to determine. Greenleaf on Evidence, Redfield’s edition, Sec. 440, citing Lockwood v. Lockwood, 2 Curtis, 309; Dillon v. Dillon, 3 Curtis, 96, 102. See also Dickinson v. Fitchburg, 13 Gray, 546.
Testimony of Expert, how Impeached.—Sometimes, on cross-examination or otherwise, the fact becomes known that the witness who is proposed as an expert has expressed an opinion on the subject in hand contrary to that which he has given upon the witness-stand, and the question has been raised as to establishing that fact at the outset and before his testimony goes before the jury, in order to enable the trial judge to determine whether he is competent. The rule in that case is that the testimony as to his prior expression of opinion is not to be received at that time, but will come properly up as rebuttal, he having been asked upon his cross-examination, giving time and place, whether he has made the statements attributed to him. An expert witness may in other respects be impeached like any other witness, that is, by the oaths of persons who know him and have known his reputation, and who testify that his reputation for truth and veracity is bad and that they would not believe him under oath. He may also be impeached by producing witnesses to prove that his special knowledge or technical skill is not reliable or adequate to the undertaking which he has assumed. But this testimony must be from personal knowledge of the man and not from general reputation. Wharton on Evidence, Sec. 437; Le Rose v. Commonwealth, 84 Pa. St., 200.[183]
General Rule as to Required Amount of Skill and Experience Stated.—The general rule may be stated thus, as derived from these and other authorities:
The extent of the previous study and investigation, and the amount of skill and information which must be shown, will depend upon the facts of each particular case. But some special and peculiar knowledge or skill must be established, the amount of it to be determined by the trial judge in his discretion. The possession of such knowledge and skill is presumed in medico-legal cases if the witness is a licensed practitioner.
Some Practical Suggestions as to Conduct of Witnesses on the Stand.—In this preliminary examination, the conduct and demeanor of the witness are of no little importance, because it is then and there that he makes his first impression upon the court and jury. He should be perfectly open and unreserved in stating his means of special information, in explaining what are the limits of his personal experience and the extent of his reading; but, at the same time, it would be well for him to avoid all appearance of self-glorification and all tendency to exaggerate his individual acquirements. Often has it occurred that expert witnesses of undoubted capacity and honesty, who are unfortunately grandiose and self-assertive in their manner, have, however honest and able they might be, lost entirely their weight with the court and jury by undue self-complacency and exaggeration of their personal qualifications, during their preliminary examination. This is a matter requiring tact and judgment and nerve, and should be fully understood between counsel calling him and the witness, before the witness is placed upon the stand. In that event, it will be quite safe for the witness to closely follow the questions of counsel by his answers, and to volunteer little or nothing. If his answers are not full and complete enough, counsel can renew the question in the same or in other form or carry the matter into greater detail. If, on the other hand, his answer is too full or he appears too eager, he may create a prejudice against him which nothing can overthrow, and which the art of counsel upon the other side in cross-examination and in making comments upon his testimony when summing up before the jury, will very effectually use to destroy his weight as an expert.[184]
Scope and Extent of Examination of Expert Witnesses.—Having stated how experts may be summoned and qualified, it remains to consider the scope and extent to which they may be examined.
The advancement of the sciences and the progress of research in special fields of knowledge have made expert testimony of large importance during the present century. The basis of its admission is the fact that there are certain processes of reasoning which an ordinary jury is incapable of performing, even with the assistance of courts and lawyers. Oftentimes in the administration of justice in our courts, proof is given of circumstances which although admitted would have little or no significance in the mind of an ordinary juror, and which he would be unable to contrast and compare with other facts, successfully, without the aid of those more familiar with scientific matters and the inductive process of reasoning than he is. In such cases it is necessary that the jury should be specially enlightened by persons who have, through training, skill and experience, acquired the power to enlighten them. A common instance and illustration of this matter is to be found in the case of homicide by poisoning. A human body is found dead; externally there may be no indicia to show positively the cause of death. Under such circumstances the laws of all civilized countries permit what is called a post-mortem examination by skilled physicians, who, finding no external evidences of the cause of death, are permitted by the officers of the law to remove the internal portions of the body for special and careful examination. If this discloses traces of inflammation or of lesions of an abnormal character, further power is vested in the authorities to have at the expense of the State a chemical examination of the internal organs. If this examination, which is necessarily long and excessively technical, results in the discovery of any poisonous substance, such as would produce death, and if it is found in sufficient quantities to produce death, these persons who made the post-mortem examination and discovered the outward indications of the administration and effects of the poison, and the chemists who discovered the poison itself in the tissues of the body, in sufficient quantities to produce death, are called as experts before the jury. The post-mortem examiners explain what the appearance of the body was, as distinguished from the appearances of the body of an individual who had died from natural causes. The chemist describes his course of experimentation, the various deductions which he made from his experiments, the tests which he applied in his investigation in discovering poison, and is then allowed to testify that the poisonous substance was found in sufficient quantities to produce the physical appearances which the post-mortem examiners have described, and to accomplish the death of the human being in whose body the poison was found. It is obvious that the power of observation and the skill, which the skilled chemists and physicians used as the basis of their reasoning in this case, were such as an ordinary man, unskilled and inexperienced, would not possess, and the ability to use them must have come from the study of treatises on such subjects, and from teaching and experience, to such an extent as to entitle the persons so testifying to be considered by the courts as qualified to express an accurate and sound opinion on the matters and things under investigation. Thus it appears how, in such cases, a departure became essential to the successful administration of justice, from the strict rule that witnesses shall testify solely to matters of fact and observation, and why it has long been considered that some witnesses must be allowed to testify to opinions and conclusions.
Again, in a like case, a body is found bearing evidences of wounds or bruises. The question to be determined is whether they were inflicted before or after death; if before death, whether they were sufficient to cause death. Some wounds and injuries might be sufficiently apparent and dangerous so that the common, inexperienced eye would at once detect that they were sufficient to cause death. But in most instances this is not the case, and in such instances the testimony of experts is required by the necessity of the case, to show that the wounds and injuries were sufficient to cause death.
The General Rules Stated as to Subjects for Expert Testimony.—Hence the general rule is, that wherever the facts to be investigated are such that common experience and knowledge of men do not enable them to draw accurate conclusions, but are such that the study and experience of specialists do enable such specially endowed persons to draw accurate conclusions, then the inferences and deductions they have drawn can be testified to by those who qualify themselves before the court as persons having sufficient skill and experience as such specialists to entitle them to give opinions. The cases in which expert testimony is permitted to be given are set forth in Rogers on Expert Testimony, Sec. 6, quoting from Jones v. Tucker (41 N. H., 546), as follows:
“1. Upon questions of science, skill, or trade, or others of like kind.
“2. Where the subject-matter of inquiry is such that inexperienced persons are unlikely to prove capable of forming a correct judgment without such assistance.
“3. Where the subject-matter of investigation so far partakes of the nature of science as to require a course or previous habit of study in order to the attainment of knowledge of it.”
So also Chief Justice Shaw of the Supreme Court of Massachusetts, in New England Glass Co. v. Lovell (7 Cushing, 319), said:
“It is not because a man has a reputation for sagacity and judgment and power of reasoning that his opinion is admissible in testifying as a witness. If so, such men might be called in all cases to advise the jury, and it would change the mode of trial; but it is because a man’s professional pursuit, or his peculiar skill and knowledge of some department of science not common to men in general, enable him to draw inferences where men of common experience, after all the facts have been proved, would be left in doubt.”
To the same effect see Muldowney v. Illinois Central R. R. Co., 36 Iowa, 472; Wharton on Evidence, Sec. 436; Greenleaf on Evidence, Sec. 441.
Qualifications of this General Rule.—The extent to which an expert witness can go in giving his opinion is limited to matters of science and skill, and does not extend to the expression of views on matters of legal or moral observation, or the manner in which others would probably be influenced if the parties had acted in one way rather than in another. Campbell v. Richards, 5 B. & Ad., 345.
So it has been held that the question whether a physician has honorably and faithfully discharged his duty in a given case, either to his medical profession or to his patient, is not a question of science but of pure ethics, upon which the jury is as competent to decide as any one else, and in such a case an opinion would not be allowed to be given either by another medical practitioner or by a professor in the science of morals. Rogers on Expert Testimony, Sec. 11, citing Ramadge v. Ryan, 9 Bing., 333.
There are also some matters of fact which apparently transcend the dividing line between common experience and judgment and scientific experience and judgment, as to which expert testimony is not receivable, but the jury and court must weigh the facts and draw the inferences for themselves. An interesting example of this is found in the case of Manke v. The People, 78 N. Y., 611 (17 Hun, 410), cited in Stephens’ “Digest of the Law of Evidence,” p. 107, note H, decided in the New York Court of Appeals a few years ago. In that case one Adolf was killed by a gunshot, and pieces of paper were found near the scene of the homicide bearing certain marks. An expert was called upon to say whether they were powder-marks, and whether the condition of the paper was such that in his opinion it was wadding which had been fired from a gun. This evidence was held to be inadmissible by the General Term of the Supreme Court, and this decision was affirmed by the Court of Appeals. These courts held that the question as to whether this was a wad fired from a gun was a matter which the jury was as competent to judge of as the witness. In delivering the opinion at General Term, Presiding Justice Talcott said that this case was very close to the border line, but in his judgment it was beyond the province of experts and within the province of jurors.
Nevertheless, in that case the evidence of chemists who had examined the wadding, and had discovered the marks on it which were said to be powder-marks, and upon analysis had determined that they were powder-marks, or that they were marks of powder which had exploded, would have been clearly admissible.
The subjects concerning which medical men may be called upon to testify as experts are as numerous as the diseases, injuries, mental and physical conditions of the human race which fall within the range of the practice of medicine and surgery. It is therefore practically impossible to give them in detail.[185]
Practical Suggestions and Admonitions Embodied in Rules.—It is deemed advisable that the following practical suggestions and admonitions to physicians, concerning their duties as expert witnesses, shall here be given.
First: A physician should refuse to testify as an expert unless he is conscious that he is really qualified as an expert.
Second: After accepting the responsibility, his first duty should be to make a diligent examination and preparation for his testimony, unless it is upon a subject with which he is familiar and which he is satisfied that he has already exhausted, by reading the best authorities that he can find, and by careful reflection upon particular questions as to which his opinion will be asked.
Third: Where he is to make an examination of facts, such as the post-mortem examination of a body, a chemical analysis or an examination of an alleged insane person, he should insist upon having plenty of time and full opportunity for doing his work thoroughly. He should take particular pains to make his examination open and fair, and, if possible, should invite opposing experts to co-operate with him in it.
Fourth: He should be honest with his client before the trial in advising him and giving him opinions, and upon the trial should preserve an absolutely impartial attitude, concealing nothing, perverting nothing, exaggerating nothing.
Fifth: On the preliminary examination as to his qualifications as a witness he should be frank and open in answering questions. He should state fully the extent and the limits of his personal experience and of his reading upon the subject, without shrinking from responsibility, yet without self-glorification.
Sixth: He should be simple, plain, and clear in his statement of scientific facts and principles, avoiding the use of technical language, and trying to put his ideas in such form that they will be grasped and comprehended by men of ordinary education and intelligence.
Seventh: He should avoid stating any conclusions or principles of which he is not certain, but having an assurance that he is right he should be firm and positive. He should admit the limitations of his knowledge and ability. Where a question is asked which he cannot answer, he should not hesitate to say so; but he should refuse to be led outside the subject of inquiry, and should confine his testimony to those scientific questions which are really involved in the case, or in his examination of the case.
Eighth: And finally, he should always bear in mind that at the close of his testimony an opportunity is usually given to him to explain anything which he may be conscious of having said, which requires explanation; and partial statements which need a qualification to make them a truth. This is the physician’s opportunity to set himself right with the court and with the jury. If the course of the examination has been unsatisfactory to him, he can then, by a brief and plain statement of the general points which he has intended to convey by his testimony, sweep away all the confusion and uncertainty arising from the long examination and cross-examination, and can often succeed in producing for the first time the impression which he desires to produce, and can present the scientific aspects of the case briefly and correctly.
Probably no man was ever so gifted as to be able in practice to carry out all of these principles in giving medical testimony. If he could, he would be the ideal expert witness. But the principles are, after all, simple and easily followed in the main. Any physician who knows his subject and who has a clear head and the ordinary faculty of expression, by observing these principles can make himself invaluable as an expert witness. There is no branch of the profession which brings a broader fame, greater influence, or larger emoluments than this. There is no branch, on the other hand, in which men of real ability make more lamentable failures.